In dental technology, it is known to preselect or activate the handpieces or, respectively, the supply agents thereof upon detachment of the handpieces from their respective deposit devices or holders. To this end, correspondingly fashioned switch elements are located in or at the holder with one switch being provided for each handpiece. The switch elements can be microswitches, light barriers or inductive sensors as well as shown in EP-0 005 791-B1.
It is a disadvantage that a switch element for each handpiece must be present at practically every holder. Since the holders are usually designed as claw-shaped receiving elements in the form of an open ring, it is necessary, for example, given arrangement of a light barrier, to provide a transmitter and a receiver for each side of the opening. Given the standard practice of equipping of a dental apparatus with at least four through six handpieces, this means that the plurality of light barriers corresponding to each handpiece must be provided even when fewer handpieces are used or, respectively, desired by the physician or dentist.
Further disadvantages include the possibility of disturbances at the transmitter or receiver due to environmental or other influences. With light barriers, for example, disturbances can arise due to the incidence of extraneous light or due to contaminants. Embodiments with mechanical switch elements are also not free of disturbances. For example, the adjustment can be modified or worn due to frequent switching, so that the switch elements no longer work in a reliable manner.
A further, critical disadvantage given the known embodiments is that a deposit of a handpiece at a different location, for example at an interim deposit of a tray, is not possible or is only possible on the basis of additional, manual switching events.